Vertical draft relief



Aug. 17, 1965 1.. P. HINE. JR

VERTIGAB DRAFT RELIEF Filed D80. 2, 1965 Fig.4

INVENTOR.

Lou/s P. H/NE J2.

ATTOENEYE.

United States Patent 3,200,811 VERTICAL DRAFT RELIEF Louis P. Hine, In,Elyria, Ohio, assignor to The C. A. Olsen Mfg. (10., a corporation of()laio Filed Dec. 2, 1963, Ser. No. 327,228 1t? Claims. (Cl. 126116)This invention relates to gas fired appliances such as gas furnaces andconcerns particularly vertical draft relief.

An object of the invention is to provide improved, attractive gas firedfurnaces, substantially unaffected by downdraft and without excessiveback pressure, without producing carbon monoxide.

Conventionally, gas fired furnaces are provided with a draft hood tovent the flue products without altering efliciencies or flamecharacteristics under varying chimney updraft conditions. The draft hoodis also intended under chimney downdraft conditions to vent thedowndraft to the extent that it does not disturb flame characteristicsand create carbon monoxide.

To accomplish this downdraft venting on a built-in draft hood usuallymeans that a sloping deflector baflie is built directly under the drafthood relief opening that deflects the downdraft out through the front ofthe furnace so that the burners themselves are not affected by airvelocities or flue products. Excessive deflection must be avoidedbecause any great deflection creates a back pressure which slows downthe escape of the flue products spoiling combustion and producing carbonmonoxide.

However, it has been considered desirable to improve the appearance of agas fired furnace by the elimination of the opening in the front of thefurnace. This necessitates deflecting the downdraft in a defferentdirection. Merely turning the downdraft 180 and discharging throughenlarged openings in the horizontal top panel of the furnace tends toresult in back pressures becoming so severe inside the draft hood thatflames float off burners and carbon monoxide is produced in excessiveamounts.

It is accordingly an object of the invention to overcome the foregoingdifficulties and to provide reliable, safe draft hoods.

Other and further objects, features and advantages of the invention willbecome apparent as the description proceeds.

In carrying out the invention in accordance with a preferred formthereof a reshaped draft hood is provided with larger venting areas andmeans are provided to split the downdraft gradually with a deflectorbaffle. Back pressure is overcome by providing a modified venturi effectby baffling the inner side of the draft hood.

A better understanding of the invention will be afforded by thefollowing detailed description considered in conjunction with theaccompanying drawing in which:

FIG. 1 is a front elevation of a gas fired furnace employing an improveddraft hood with vertical draft relief.

FIG. 2 is a view of a vertical section of the furnace of FIG. 1represented as cut by a central vertical plane.

FIG. 3 is a top view, and

FIG. 4 is a fragmentary view of the furnace and draft hood representedas cut by a vertical plane with a portion of the draft hood broken awayto expose the interior.

The invention is illustrated as employed in a sheet metal, gas firedfurnace having a front wall 11, side walls 12 and a horizontal top panel13 forming the upper portion of a bonnet through which a vertical ventor flue pipe 14 extends.

The front wall 11 of the furnace is continuous and without any openingsexcept for an opening 15 to receive gas supply pipes (not shown) andprovide access to a conventional burner or burners 16 which extendthrough openings 17 in a fire box wall 18. There is a flue-product inlet19 at the upper portion of the fire box wall 18.

Within the furnace bonnet there is a draft hood 2.1, also preferablycomposed of sheet metal. The draft hood 21 is substantially in the formof a flat-sided box shown as trapezoidal, formed of joined wallsincluding a top wall 22, side walls 23, a front wall 24, a back wall anda bottom wall 26. Although the invention does not exclude a rectangularconstruction the side walls 23 are shown as slanting inward toward thefront of the furnace. In the construction illustrated the back wall 25of the draft hood 21 is secured against the fire box wall 13 although itmay be a continuation or form a part of the fire box wall 18. The flueproduct inlet 19 constitutes an opening in the back wall 25' of thedraft hood 2?..

The draft hood top wall 22 has a flue pipe opening or vent opening 27,and is preferably formed with a flange 28 around the edges of theopening 27 to form a nipple for connection to the flue pipe 14 whichpasses through the top panel 13 of the furnace and terminates at the topwall 22 of the draft hood 21, said top wall being spaced from the upperhorizontal panel 13 of the furnace. The front wall 24 and the side walls23 are continuous.

The bottom wall 26 has a draft relief opening 29 which is larger thanthe flue pipe opening 27. Although the invention is not limited thereto,for the sake of illustration the flue pipe 14 has been represented asbeing circular in cross section but the openings 27 and 29 are shown asrectangular. The opening 29 is larger than the. opening 2'7 to guardagainst creating excessive back pressure in the event of downdraftthrough the flue pipe 14. In addition the downdraft is split graduallyby providing a deflector bathe 31. In order to provide still furtherassurance of overcoming back pressure a modified venturi effect isprovided by baffiing the inner side of the draft hood by means of aventuri bafile 32 extending upward from the bottom wall 26 of the drafthood 21.

The deflector baffle 31 is shown as composed of sheet metal extendinghorizontally further than the bottom wall as of the draft hood 21,preferably having a rising center 33 and upwardly slanted ends or edges34. The venturi baffle 32 is shown as composed of straight vertical sidewalls 3e" extending from front to rear between the front wal 24 and therear wall-25 0f the draft hood 21. The venturi baffle side walls 35 maybe joined to the bottom wall 2% at the sides of the opening 29 therein.If desired, as shown, the vertical walls 35 of the venturi baflie 32 maybe bent up from the same sheets of metal forming the bottom wall 26.

referably a greater venturi effect is accomplished by flaring the upperedges 35 of the vertical walls 355 of the venturi baffle 32 and also theedge 37 of the opening 19 in the back wall 25 to form a throat.

The rising center portion 33 of the deflector baille 31 is centered withrespect to the venturi baflie 32. Enlarged openings 38 and 39 areprovided at each side on the right and left ends of the horizontal toppanel 13 of the furnace for vertical draft relief. The center risingportion 33 of the deflector baffle 31 is a ridge in the shape of aninverted V channel comprising upwardly bent slanting portions 41 and 42of the sheet material of which the deflector baffle 31 is formed; andthe deflector baffle 31 extends in the direction from front to rearbetween the furnace front panel 11 and the fire box vertical wall 18 sothat no upwardly sloping edges are required at the front and rear endsof the deflector baffle 31.

Referring to FIG. 2 of'the drawing it will be apparent that the productsof combustion of the burners l6 constituting the flue products rise andenter the opening 19 in the draft hood 21, normally continuing upwardthrough the flue pipe 14. Varying updraft conditions in the chimney towhich the flue pipe 1 is connected do not alter efficiencies or flamecharacteristics of the burners 16 since the flue products are vented tothe draft hood 21 which is substantially larger in horizontal crosssectional area than the flue pipe 14.

In the event of downdraft through the chimney and the flue pipe 14, theflue products in the flue pipe 14 do not disturb the flames of theburners llti since they are vented downward through the throat of theventuri baflie 32, through the opening 29. Thereafter they are split bythe sloping walls 41 and 4-2 of the center rise portion 33 of thedeflector baffle 31, then diverted upward by the upwardly sloping ends34 of the deflector baflle 31 to escape through the enlarged openings 38and 39 in the horizontal top panel 13 of the furnace.

The downdraft path through the flue pipe 14 is represented by thearrows4t) and, in case of chimney downdraft, the downdraft path of the flueproducts from the flue product opening 19 is in the direction of thearrows 43. Creation of back pressure is avoided by the ample size of theventuri throat in the venturi baffle 32 so that the combined flueproducts follow the paths of curved arrows 44 downward against thedeflector baflle 31 thence along arrows 45 and upward in the directionof arrows 46. As soon as the downdraft stops, of course, the flueproducts resume their usual path upward from the burner 16 through theopening 19 and directly upward through the flue pipe 14.

While the invention has been described as embodied in concrete form andas operating in a specific manner in accordance with the provisions ofthe patent statutes, it

should be understood that the invention is not limited thereto, sincevarious modifications will suggest themselves to those skilled in theart without departing from the spirit of the invention.

What is claimed is:

1. In a gas fired furnace a draft hood therefor, and a furnace bonnetwith a substantially horizontal wall at the top with a flue pipe openingtherein and draft relief openings on either side thereof, and a fluepipe extending through said flue pipe opening terminated below saidbonnet top wall, said draft hood comprising:

(a) a top wall with an openinng therein connected to said flue pipe,

(b) vertical front and side walls,

(0) a vertical rear wall with a flue product opening therein,

((1) a bottom wall with a relief opening therein larger than the fluepipe opening in the top wall, and

(e) a horizontally extending deflector baflie spaced from and below thebottom wall.

2. A draft hood as in claim ll wherein the deflector baffle comprisessheet material larger than said bottom wall with upward slanting outeredges and a raised center narrower than the relief opening in the bottomwall.

3. In a gas fired furnace, a draft hood therefor and a furnace bonnetwith a substantially horizontal wall at the top with a flue pipe openingtherein with draft relief openings on either side thereof, a flue pipeextending through said flue pipe opening terminating below said bonnettop wall, said draft hood comprising in combination:

(a) a top wall with an opening therein provided with a flange connectedto said flue pipe,

(b) vertical front and side walls,

(c) a vertical rear wall with a flue-product opening locatedapproximately in the upper half thereof,

(d) a botom wall with a relief opening therein,

(e) an internal venturi baflle connected to said relief opening andextending substantially vertically from the bottom wall with outwardlyflaring upper edges, and

(f) a horizontally extending deflector baflle spaced from and below thebottom wall.

4. In a gas fired furnace:

(a) a furnace bonnet with a substantially horizontal wall at the topwith a flue pipe opening therein and draft relief openings on eitherside thereof,

(b) a flue pipe extending through said flue pipe opening terminatingbelow said bonnet top wall, and

(c) a draft hood comprising:

(1) a top wall spaced from said furnace bonnet top wall with an openingtherein connected to said flue pipe, (2) vertical front and side walls,(3) a vertical rear wall with a flue product opening therein, (4) abottom wall with a relief opening therein,

and (5 means for deflecting flue products issuing from said bottom-wallrelief opening upward toward said draft relief openings in the furnacebonnet. 5. The combination of claim 4 wherein the draft hood includes aninternal venturi baffle connected to said bottom wall relief opening andextending upward from said bottom wall.

6. In a gas fired furnace a draft hood therefor, and a furnace bonnetwith a substantially horizontal wall at the top with a flue pipe openingtherein and draft relief openings on either side, and a flue pipeextending through said flue-pipe opening terminating below said bonnettop wall,

said draft hood comprising in combination:

(a) a top wall with an opening therein connected to said flue pipe, (b)vertical side walls, (c) a vertical rear wall with a flue productopening located approximately in the upper half thereof, (d) a bottomwall with relief opening therein,

(e) an internal baffle connected to said relief opening and extendingupwardly from the bottom wall, and

(f) means for deflecting upwardly any flue products issuing from saidrelief opening.

'7. A draft hood as in claim 6 in which the deflecting means constitutesa horizontally extending deflector baffle spaced from and below thebottom wall.

8. A draft hood as in claim '7 wherein the deflector bafllc comprisessheet material larger than said bottom wall with a central upwardlydirected inverted V-channel formed therein.

9. In a gas fired furnace:

(a) a furnace bonnet with a substantially horizontal wall at the topwith a flue pipe opening therein and draft relief openings on eitherside thereof,

(b) a flue pipe extending through said flue pipe opening terminatingbelow said bonnet top wall, and

(c) a draft hood comprising:

(1) a top wall spaced from said furnace bonnet top wall with an openingtherein connected to said flue pipe,

(2) vertical front and side walls,

5 (3) a vertical rear wall with a flue product opening therein, (4) abottom wall with a relief opening therein, (5 an internal venturi baflleconnected to said bottom wall relief opening and extending upward fromsaid bottom wall, and

(d) a deflector bafi le spaced from and below the bottom wall of saiddraft hood and extending beyond the draft hood to divert any flueproducts issuing from said bottom Wall relief opening upward toward saiddraft relief openings in the furnace bonnet.

10. The combination of claim 9 wherein the deflector baflie comprisessheet material with a center ridge extending the length of the baffleand upturned ends extending the length of the bafile.

FOREIGN PATENTS 8/31 Germany. 11/32 Germany.

OTHER REFERENCES 10 Vaillant: German printed application No. 1,045,065,

printed November 1958 (V 7823 X/366).

FREDERICK L. MATTESON, IR., Primary Examiner.

15 JAMES W. WESTHAVER, Examiner.

1. IN A GAS FIRED FURNACE A DRAFT HOOD THEREFOR, AND A FURNACE BONNETWITH A SUBSTANTIALLY HORIZONTAL WALL AT THE TOP WITH A FLUE PIPE OPENINGTHEREIN AND DRAFT RELIEF OPENINGS ON EITHER SIDE THEREOF, AND A FLUEPIPE EXTENDING THROUGH SAID FLUE PIPE OPENING TERMINATED BELOW SAIDBONNET TOP WALL, SAID DRAFT HOOD COMPRISING: (A) A TOP WALL WITH ANOPENING THEREIN CONNECTED TO SAID FLUE PIPE, (B) VERTICAL FRONT AND SIDEWALLS, (C) A VERTICAL REAR WALL WITH THE FLUE PRODUCT OPENING THEREIN,(D) A BOTTOM WALL WITH A RELIEF OPENING THEREIN LARGER THAN THE FLUEPIPE OPENING IN THE TOP WALL, AND